package com.junmoxiao.baseadmin.utils;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;

/**
 * @Author 君沫笑
 * @Description 图片验证码
 * @Date 2020-10-14 1:30 下午
 **/

public class VerifyUtil {
    private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生数字与字母组合的字符串
    private int width = 75;// 图片宽
    private int height = 25;// 图片高
    private int lineSize = 40;// 干扰线数量
    private int stringNum = 4;// 随机产生字符数量

    private Random random = new Random();

    /**
     * @Author 君沫笑
     * @Description 获得字体
     * @Date 1:37 下午 2020/10/14
     * @Param []
     * @return java.awt.Font
     **/

    private Font getFont() {
        return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
    }

    /**
     * @Author 君沫笑
     * @Description 获得颜色
     * @Date 1:37 下午 2020/10/14
     * @Param [fc, bc]
     * @return java.awt.Color
     **/

    private Color getRandColor(int fc, int bc) {
        if (fc > 255)
            fc = 255;
        if (bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc - fc - 16);
        int g = fc + random.nextInt(bc - fc - 14);
        int b = fc + random.nextInt(bc - fc - 18);
        return new Color(r, g, b);
    }

    /**
     * @Author 君沫笑
     * @Description 生成随机图片
     * @Date 1:36 下午 2020/10/14
     * @Param [response]
     * @return java.lang.String
     **/

    public String getRandcode(HttpServletResponse response) {
        // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        Graphics g = image.getGraphics();// 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
        g.fillRect(0, 0, width, height);//图片大小
        g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 20));//字体大小
        g.setColor(getRandColor(110, 133));//字体颜色
        // 绘制干扰线
        for (int i = 0; i <= lineSize; i++) {
            drowLine(g);
        }
        // 绘制随机字符
        String randomString = "";
        for (int i = 1; i <= stringNum; i++) {
            randomString = drowString(g, randomString, i);
        }
        g.dispose();
        try {
            // 将内存中的图片通过流动形式输出到客户端
            ImageIO.write(image, "JPEG", response.getOutputStream());
        } catch (Exception e) {
            System.out.println(e.toString());
        }
        return randomString;
    }

    /**
     * @Author 君沫笑
     * @Description 绘制字符串
     * @Date 1:36 下午 2020/10/14
     * @Param [g, randomString, i]
     * @return java.lang.String
     **/

    private String drowString(Graphics g, String randomString, int i) {
        g.setFont(getFont());
        g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
                .nextInt(121)));
        String rand = String.valueOf(getRandomString(random.nextInt(randString
                .length())));
        randomString += rand;
        g.translate(random.nextInt(3), random.nextInt(3));
        g.drawString(rand, 12 * i, 16);
        return randomString;
    }

    /**
     * @Author 君沫笑
     * @Description 绘制干扰线
     * @Date 1:36 下午 2020/10/14
     * @Param [g]
     * @return void
     **/

    private void drowLine(Graphics g) {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(13);
        int yl = random.nextInt(15);
        g.drawLine(x, y, x + xl, y + yl);
    }

    /**
     * @Author 君沫笑
     * @Description 获取随机的字符
     * @Date 1:36 下午 2020/10/14
     * @Param [num]
     * @return java.lang.String
     **/

    public String getRandomString(int num) {
        return String.valueOf(randString.charAt(num));
    }

}
